The man developed the disease after undergoing a liver transplant following chronic infection with hepatitis B. He continued to show signs of abnormal liver function, said Sridhar, with no obvious cause.

The report said that the victim was 56-year-old man in may last year, transplanted the liver.

The world's first human case of rat disease has been diagnosed in China.

Rodent problems have worsened in Hong Kong with experts saying they found signs of rat infestation near his home, and suspected he had consumed something that had been in touch with rat faeces.

A sustained period of hot and humid weather has caused rodent problems in Hong Kong to escalate, multiple sources reported. It is a liver disease that affects 20 million people globally each year, according to the World Health Organization.

Hepatitis E is a major health threat in developing countries in Africa and Asia and in the past has been contracted from eating undercooked pork and deer meat.